However, the laptop's smaller design required a few more design compromises. For instance, the 8GB of soldered RAM is the only option; unlike the 15-inch model, there doesn't appear to be room on the logic board to solder on an additional 8GB. There's no discrete graphics chip, either. We'll definitely look into the performance more once we have a sample to review, but we suspect these limitations could push some potential users up to the 15-inch model.

Enlarge/ The 13-inch Retina MacBook Pro apparently has no room for a discrete GPU or more than 8GB of RAM.

The 13-inch Retina MacBook Pro uses an asymmetrical lithium-ion cell configuration for its battery. Two of the cells are easily removed with screws, though the remaining four are glued to the aluminum unibody shell, just like the 15-inch model. iFixit's Miro Djuric told Ars that the adhesive does seem slightly easier to work with in comparison to the strong adhesive on the 15-inch model.

In an interesting move, the battery on the 13-inch machine is not glued over the trackpad assembly, which makes it fairly easy to access and replace. Instead, Apple tucked the SSD module underneath the trackpad, connecting to the logic board with a ribbon cable.

Enlarge/ There's plenty of room underneath the trackpad for a much larger SSD module.

However, the space underneath the trackpad is large enough to hold a slim 2.5-inch form factor drive. Djuric noted that a 9.5mm SSD didn't quit fit, but "only by a smidge." A 7mm or 5mm drive could fit, though it would require a custom cable to connect to the logic board's SATA port. Still, such a solution may offer potentially less expensive SSD replacements.

Unsurprisingly, iFixit gave the 13-inch Retina MacBook Pro a 2/10 score for repairability. The drive module and trackpad are easier to replace, and the battery is "slightly" easier to work with, giving it a one point advantage over the 15-inch Retina MacBook Pro. However, everything is tucked inside with Apple's pentalobe screws, RAM is impossible to upgrade or replace, and the fused Retina display module is a pricey, integrated unit.